Apollo+40: Where No Man Has Gone Before

At 2:50:37 MET (Misson Elapsed Time) - 10:41 AM EST - Apollo 8 became unlike the any previous voyage in Human history. The third stage of Saturn V booster 503 was relit. This is known as Translunar Injection (TLI), and sent Borman, Lovell, and Anders on their way to the Moon.

Fellow Astronaut Michael Collins, originally to have been an Apollo 8 crewmember but who was replaced by Jim Lovell due to a back injury, acted as one of the spacecraft communicators in Mission Control for Apollo 8. Collins' first stint for the flight was for the launch and TLI phases. In Collins' wonderful memoir, Carrying the Fire, he recounts the moment (pages 305-306, emphasis mine):

The next big event was reigniting the third-stage Saturn V engine to set
sail for the moon. Known as TLI (translunar injection), this burn had to
take place precisely at 10:40 Eastern Standard Time [NASA mission reports
indicate 10:41], which meant that before then the crew had to check everything
on a long list of equipment, each item of which had been deemed vital to making
the trip. If something was broken, we should know about it now, not after TLI,
when trajectories become very complicated. Fortunately, the checks went
smoothly, and spacecraft 103, Dave Scott's pampered baby, seemed to be purring
along flawlessly. Now the big moment came. As we counted down to
S-IVB ignition for TLI, a hush fell over Mission Control. TLI was what
made this flight different from the six Mercury, ten Gemini, and one Apollo
flighs that had preceded it, different from any trip man had ever made in any
vehicle. For the first time in history, man was going to propel himself past escape velocity, breaking the clutch of our earth's gravitational field and coasting into outer space as he had never done before. After TLI there would be three men in the solar system who would have to be counted apart from all the other billions, three who were in a different place, whose motion obeyed different rules, and whose habitat had to be considered a separate planet. The three could examine the earth and the earth could examine them, and each would see the other for the first time. This the people in Mission Control knew; yet there were no immortal words on the wall proclaiming the fact, only a thin green line, representing Apollo 8 climbing, speeding, vanishing - leaving us stranded behind on this planet, awed by the fact that we humans had finally had an option to stay or leave -

and had chosen to leave.

TLI completed successfully just over five minutes later. Godspeed Apollo 8!